void main(){
  int score=90;
  if(score>=90){
    if(score==100){
      print('S');
    }else{
      print('A');
    }
  }else if(score>=60){
    print('B');
  }else{
    print('C');
  }

  String lang='JavaScript';
  switch(lang){
    tag:
    case 'Dart':
      print('Flutter');
      break;
    case 'JavaScript':
      print('Node');
      continue tag;
    case 'Python':
      print('Django');
      break;
    default:
      print(null);
  }
}
